粉煤灰分选、脱炭及生产工艺研究

针对国内火力发电厂粉煤灰未燃炭含量过高的问题,对粉煤灰的理化特征、未燃炭在粉煤灰颗粒中的分布进行了研究,分析比较了不同分选、脱炭技术及分选、脱炭生产工艺流程,分析了粉煤灰分选脱炭的经济效益.     

高炭粉煤灰浮选脱炭试验研究

高含炭量的粉煤灰是一种不可被直接利用的固体废弃物。为降低高炭粉煤灰的烧失量,对高炭粉煤灰进行脱炭试验研究。本文通过磨矿试验确定高炭粉煤灰原灰最佳磨矿时间为1.25 min;通过浮选药剂制度试验确定磨细高炭粉煤灰最佳浮选药剂制度为仲辛醇用量为4 kg/t,煤油用量为12 kg/t;通过浮选工艺试验,确定磨细高炭粉煤灰最佳浮选工艺为叶轮机转速2 000 r/min、刮泡时间8 min、矿浆浓度120 g/L和单位面积充气量0.30 m³/(m²·min)。通过上述试验,最终可得到烧失量为0.63%,产率为60.64%的脱炭粉煤灰,烧失量可达到Ⅰ级灰要求。     

电厂粉煤灰降炭提质技术工艺系统研究

针对发电厂排放的粉煤灰烧失量较高不能直接利用的现状,山东煤机装备集团公司利用自主研制的专用旋流—静态微泡浮选柱对粉煤灰进行了脱炭的浮选试验研究,并获得了成功应用;粉煤灰降炭提质湿法浮选技术工艺分选设备简单,运行成本低,回收率高达90%以上,创造了可观的经济效益和社会效益。     

非线性电场中电选粉煤灰颗粒分离过程研究

在粉煤灰摩擦电选脱炭中,针对颗粒因带电荷质比小导致分选效率不高的问题,提出了一种新的非线性电场结构;在建立非线性电场二维模型和数学模型的基础上,对带电粉煤灰颗粒的运动过程进行了数值模拟,深入研究了颗粒荷质比、入射速度、电场强度和极板最小间距等因素对粉煤灰颗粒分离行为的影响,探索了非线性电场用于74μm粉煤灰颗粒高效脱炭的可行性,获得了操作参数的合理范围,为实现粉煤灰电选高效脱炭提供了新思路。     

脱碳粉煤灰资源化特性及公路修复技术研究

根据粉煤灰中炭粒与无机灰粒的电性差异及其资料化特性，利用高压静电脱炭技术制成脱炭粉煤灰，本文主要研究了利用脱炭粉煤灰资源化特性和高效早强减水剂掺用技术，进行了公路混凝土路面的修复技术试验，结果表明了脱炭粉煤灰用于公路混凝土路面修筑时可替代水泥量20％，路面质量达到了国家工程标准，较好地解决了公路路面工程中直接利用粉煤灰所存在的主要问题。     

某锡石多金属硫化矿的选矿工艺研究

采用"浮选-重选"联合工艺对锡石细粒嵌布、矿物组分复杂的锡石多金属硫化矿进行研究。分析了矿石的性质,考查了"优先浮选-重选"和"混合浮选-重选"两种工艺流程的技术经济指标。结果表明:优先浮选-重选工艺流程中,锡的综合回收率为40.43%,铜的回收率为65.87%;与混合浮选-重选工艺流程相比,优先浮选-重选工艺的锡综合回收率低2.49%,铜回收率高4.2%;优先浮选-重选工艺流程的处理每吨原矿的毛利润为58.46元,比混合浮选-重选工艺流程多收入13.93元。     

太西无烟煤基粉煤灰摩擦电选脱炭试验研究

针对太西无烟煤基粉煤灰未燃炭含量偏高的问题,研究分析了三种不同组分的粉煤灰理化特性,对三种粉煤灰进行了摩擦电选脱炭研究,确定了初步工艺流程,为今后粉煤灰的综合利用做好了前期准备工作。     

铬铁矿选别技术的研究进展

综述了铬铁矿资源现状及供需状况,通过对铬铁矿矿物性质及特征分析,介绍了近年来不同选矿技术在铬铁矿选别上的应用及意义;具体包括对重选、磁选、浮选、化学选矿及其他选别方法介绍,分析了不同选矿方法的适用条件及技术优势,并对铬铁矿选矿的未来发展做了展望。     

胶磷矿脱硅研究现状概述

针对胶磷矿品位低、难选,尤其是主要脉石为石英等硅质矿物难以脱除的特点,总结重选分离、电选、浮选等磷矿脱硅工艺的研究现状,为胶磷矿脱硅富磷提供参考;介绍磷矿脱硅捕收剂和脱硅抑制剂的研究现状。     

预富集技术研究进展

预富集技术主要是根据矿石矿物与脉石矿物在某种特性上的差异，利用光电选、重选、磁选、浮选及化学选等工艺提高矿石矿物入选品位，预先抛弃部分脉石矿物，从而为后续分选作业创造有利条件。概述了预富集技术的研究现状，从光电选、重选、磁选、浮选、化学选以及联合工艺等方面介绍了预富集技术在选矿领域的研究及应用，分析了各种预富集技术的优缺点，并指出采用联合工艺进行预富集是实现低贫矿石和废石资源综合利用的重要技术手段。     

Triboelectrostatic separation of fly ash and charge reversal

Triboelectrostatic separation has been investigated as a method for separating unburned carbon from coal combustion fly ash. It was found that when a fly ash is exposed to moisture before it undergoes separation, the charging properties of the components of the fly ash change significantly. The mineral and carbon components of the fly ash appear to charge oppositely to how they were charged before exposure to moisture. A correlation was found between the degree of charge reversal and the relative amounts of leachable ions, especially calcium and sodium ions, present on the surface of the ash.     

Coal surface conditioning for electrostatic separation

In analogy with froth flotation using chemical agents to enlarge the difference of hydrophobicity, this study was undertaken to examine the feasibility of enlarging the differences in surface work function of coal components to improve the electrostatic separation. Two coal specimens from Alberta having medium ash and low sulfur contents were used. Chemical agents having different physical and chemical properties were investigated in both batch and continuous operation. The results show that either maceral or ash forming mineral separations can be improved by surface treatment with organic chemicals. Improvements of more than 10% were observed. The results also show that some aromatic chemicals are better for coal maceral separation while some aliphatic agents improve ash forming mineral separation.     

Simultaneous Removal of Heavy Metals and PCDD/Fs from Hospital Waste Incinerator Fly Ash by Flotation Assisted with Hydrochloric Acid

Hospital solid waste (HSW) incinerator fly ash was designated as a special controlled waste because of its high concentrations of toxic heavy metals, polychlorinated dibenzo-p-dioxins, and dibenzofurans (PCDD/Fs). Most of the PCDD/Fs along with carbon constituents including powder activated carbon and unburned carbon in fly ash could be removed by column flotation on the basis of their hydrophobicity. The feasibility of extracting heavy metals from fly ash by adding a little of hydrochloric acid to the slurry during the flotation process was examined in this paper. The results showed that the acidic pulp could contribute to the high extraction ratio of the heavy metals, but the performance of decarburization and removal of PCDD/Fs was inhibited at very low pH value. Given consideration to the removal of two toxic matter including PCDD/Fs and heavy metals in HSW incinerator fly ash, the appropriate pulp pH value should be controlled at about 5. After flotation, both PCDD/Fs and heavy metals in the tailings could simultaneously meet the permitted limits of a landfill site of municipal solid waste in China. It was suggested that flotation with the assistance of an appropriate amount of acid might be a potential technology for the treatment of HSW incinerator fly ash.     

水煤浆气化炉内飞灰的形成机理

基于实验室规模的多喷嘴对置式水煤浆气化炉,利用SEM、马尔文激光粒度仪和XRD表征气化炉内飞灰的粒径分布和组成,并分析了气化炉内飞灰的形成机理。结果表明,喷嘴平面处飞灰与气化炉出口处飞灰的粒径分布及化学组成存在显著差异,不同气化阶段飞灰的形成机理也不同。气化燃烧阶段飞灰的形成机理为部分固定碳燃烧和外在矿物转化,而在焦炭气化反应阶段,飞灰的形成机理为焦炭破碎和内在矿物释放及转化。     

循环流化床锅炉脱硫灰和普通粉煤灰的特性研究

分析研究了循环流化床锅炉脱硫灰和普通粉煤灰的化学组成、矿物相组成和热行为等。研究结果表明,脱硫灰烧失量大,CaO含量高,其主要晶相为石英、方解石和硬石膏,还有少量莫来石,玻璃相含量较少。普通粉煤灰的主要晶相为莫来石和石英相。扫描电镜观察,普通粉煤灰主要以球形玻璃微珠为主,球形微珠表面光滑。脱硫灰则以不规则形状的颗粒为主,几乎无球形颗粒。两种粉煤灰的红外光谱分析和差热分析也表现出明显差异,主要归因于脱硫灰中大量存在的硬石膏和方解石。     

Detoxification of medical waste incinerator fly ash through successive flotation

Medical waste incinerator (MWI) fly ash is considered hazardous waste because it contains hypertoxic polychlorinated dibenzo-p-dioxins and dibenzofurans as well as heavy metals. To detoxify both substances, successive flotations of MWI fly ash were performed. The first step involved decarburization flotation, whereby 91.0% of the dioxins in MWI fly ash were transformed into a froth product. In the second step (ion flotation), the influence of ionic strength on heavy metals recovered from both raw and stimulated filtrates was explored. The results revealed that the optimal conditions were sodium dodecyl sulfate at 480 ppm, methyl isobutyl carbonyl at 150 ppm, impeller speed at 2000 rpm, and flotation time of 18 min for raw leachate, through which Zn (47.0%), Pb (56.5%), Cu (57.5%), and Cd (49.1%) were recovered. For the simulated filtrate, higher removal efficiencies were noted: 60.5%, 80.6%, 69.1%, and 64.1% for Zn, Pb, Cu, and Cd, respectively. The harmful effects of the coexisting ions in the raw filtrate on heavy metal recovery were observed.     

贵州某高岭土除铁试验研究

贵州某硬质高岭土矿石中铁含量较高,不能直接利用,必须进行除铁。针对高岭土矿石中铁矿物主要为黄铁矿和弱磁性氧化铁矿物,且其嵌布粒度极细的特点,开展了浮选除铁、强磁选除铁探索试验。并在此基础上进行了强磁-酸浸及强磁-氧化酸浸试验。结果表明,采用强磁选-氧化酸浸的方法效果较好,可将高岭土中的Fe含量由1.44%降到0.75%。     

Catalytic effects of inorganic compounds on the development of surface areas of fly ash carbon during steam activation

This study was to investigate the catalytic effect of inorganic compositions present in fly ash carbons, high-unburned-carbon content fly ashes from coal-fired power plants, on the development of surface area during steam activation. Through this work, the relationships between the concentrations of alkali metals (Na and K) and a mixture of metals, Na-K-Ca and Na-K-Fe, in fly ash carbon and the surface areas of the produced activated carbon were studied.Six fly ash carbons were selected as feedstocks for activated carbon. SEM/EDS studies showed that there are two groups of inorganic particles present in fly ash carbons, in terms of the way they are associated with carbon particles: inorganic particles that exist as free single particles, and inorganic particles that are combined with the carbon particles. A series of froth flotation tests was conducted to separate the individual inorganic particles from the fly ash carbons. The concentration of the inorganic particles was analyzed using ICP-AES before and after froth flotation separation. Studies showed that the Na-K, Na-K-Ca, and Na-K-Fe which are combined with carbon particles had catalytic effects on the development of the surface areas of activated carbons. The higher the concentration of these catalytic particles, the more significant effects they had on the development of the surface areas with increasing carbon burn-off levels.     

Determination of glass content and estimation of glass composition in fly ash using quantitative X-ray diffractometry

The proportion of amorphous or glassy material in a series of fly ashes has been evaluated by X-ray powder diffraction (XRD) using the Rietveld-based SIROQUANT software package. Several different sample preparation and processing methods were investigated, including XRD analysis of samples spiked with known masses of synthetic corundum and zinc oxide as well as techniques based on analysing the raw or unspiked fly ash directly using the SIROQUANT process. In the latter case, two different poorly crystallised silicate mineral patterns, metakaolin and tridymite, were used in the SIROQUANT processing of the raw ash XRD data to represent the amorphous constituents. The results of the different methods based on XRD of spiked samples were found to be mutually consistent, and also consistent with other published data for an international reference fly ash sample. SIROQUANT analysis of the unspiked fly ashes gave similar results, although different poorly crystallised silicate reference patterns seem to be more suited for ashes from Australian and North American sources.The mineralogy of the ashes, including the proportions of quartz, iron oxide and glassy constituents, appears to be related to the nature of the mineral matter in the relevant feed coals. Calculations based on subtracting the inferred chemistry of the crystalline minerals in the fly ashes from the total fly ash chemistry were also used to estimate the overall chemical composition of the glass fraction in each ash. The results indicate that ashes derived from lower-rank coals in the samples studied have different glass compositions to those derived from higher-rank (bituminous) materials. These different glass compositions appear to be related to several other ash properties, including particle density and particle surface area. Evaluation of glass content and composition may be significant in different aspects of ash utilisation, and also in evaluating interactions with water at ash disposal sites.     

晶体化学在氧化铜矿物浮选中的应用研究进展

晶体化学是矿物分选的重要理论基础之一,在矿物浮选领域中发挥着重要作用. 本工作总结了晶体化学的研究内容及其在氧化铜矿物浮选中的应用,介绍了氧化铜矿物晶体结构特征、表面特性及可浮性研究现状,综述了晶体化学在氧化铜矿物浮选药剂作用机理研究及浮选条件控制等方面的应用,指出了晶体化学在矿物浮选中的应用研究方向.